(Preliminary)
PL680-37/38/39
38-640MHz Low Phase Noise XO
FREQUENCY SELECTION TABLE
SEL2
0
0
0
0
1
1
1
1
SEL1
0
0
1
1
0
0
1
1
SEL0
0
1
0
1
0
1
0
1
Selected Multiplier/Output Frequency
VCO Max*
VCO Min*
Reserved
Reserved
Fin x 2
Fin x 8
Fin x 16
Fin x 4
All SEL pads have internal pull-ups (default value is ‘1’). Bond to GND to set to 0.
* Special Test Modes to help selecting the inductor value for the target output frequency.
PERFORMANCE TUNING & INDUCTOR VALUE SELECTION
Please refer to PhaseLink’s ‘PhasorV Tuning Assistance’ software to automatically calculate the optimum inductor
values. In addition, the chart below could be used as a reference for quick inductor value selection.
Use the special test modes “VCO Max” and “VCO Min” to determine the optimum inductor value. “VCO Max”
represents the high end of the VCO range and “VCO Min” represents the low end of the VCO range. The output
frequency in the “VCO Max” and “VCO Min” test modes is VCO/16. This means that the output frequencies are
around the crystal frequency that will be used. The optimum inductor value is where the target crystal frequency
is closest to the middle between the “VCO Max” and “VCO Min” output frequencies. In this case the VCO will lock
in the middle of its tuning range with maximum margin on either side.
47745 Fremont Blvd., Fremont, California 94538 Tel (510) 492-0990 Fax (510) 492-0991
www.phaselink.com
Rev 11/28/05 Page 3
PLL [ PHASELINK CORPORATION ]
